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Colwell MJ, Tagomori H, Shang F, Cheng HI, Wigg CE, Browning M, Cowen PJ, Murphy SE, Harmer CJ. Direct serotonin release in humans shapes aversive learning and inhibition. Nat Commun 2024; 15:6617. [PMID: 39122687 PMCID: PMC11315928 DOI: 10.1038/s41467-024-50394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 07/09/2024] [Indexed: 08/12/2024] Open
Abstract
The role of serotonin in human behaviour is informed by approaches which allow in vivo modification of synaptic serotonin. However, characterising the effects of increased serotonin signalling in human models of behaviour is challenging given the limitations of available experimental probes, notably selective serotonin reuptake inhibitors. Here we use a now-accessible approach to directly increase synaptic serotonin in humans (a selective serotonin releasing agent) and examine its influence on domains of behaviour historically considered core functions of serotonin. Computational techniques, including reinforcement learning and drift diffusion modelling, explain participant behaviour at baseline and after week-long intervention. Reinforcement learning models reveal that increasing synaptic serotonin reduces sensitivity for outcomes in aversive contexts. Furthermore, increasing synaptic serotonin enhances behavioural inhibition, and shifts bias towards impulse control during exposure to aversive emotional probes. These effects are seen in the context of overall improvements in memory for neutral verbal information. Our findings highlight the direct effects of increasing synaptic serotonin on human behaviour, underlining its role in guiding decision-making within aversive and more neutral contexts, and offering implications for longstanding theories of central serotonin function.
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Affiliation(s)
- Michael J Colwell
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK.
| | - Hosana Tagomori
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Fei Shang
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Hoi Iao Cheng
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Chloe E Wigg
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Michael Browning
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Philip J Cowen
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Susannah E Murphy
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK
| | - Catherine J Harmer
- University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK.
- Oxford Health NHS Foundation Trust, Warneford Hospital, Oxford, UK.
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2
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Carvalheiro J, Philiastides MG. Distinct spatiotemporal brainstem pathways of outcome valence during reward- and punishment-based learning. Cell Rep 2023; 42:113589. [PMID: 38100353 DOI: 10.1016/j.celrep.2023.113589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/05/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Learning to seek rewards and avoid punishments, based on positive and negative choice outcomes, is essential for human survival. Yet, the neural underpinnings of outcome valence in the human brainstem and the extent to which they differ in reward and punishment learning contexts remain largely elusive. Here, using simultaneously acquired electroencephalography and functional magnetic resonance imaging data, we show that during reward learning the substantia nigra (SN)/ventral tegmental area (VTA) and locus coeruleus are initially activated following negative outcomes, while the VTA subsequently re-engages exhibiting greater responses for positive than negative outcomes, consistent with an early arousal/avoidance response and a later value-updating process, respectively. During punishment learning, we show that distinct raphe nucleus and SN subregions are activated only by negative outcomes with a sustained post-outcome activity across time, supporting the involvement of these brainstem subregions in avoidance behavior. Finally, we demonstrate that the coupling of these brainstem structures with other subcortical and cortical areas helps to shape participants' serial choice behavior in each context.
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Affiliation(s)
- Joana Carvalheiro
- School of Psychology and Neuroscience, University of Glasgow, Glasgow G12 8QB, UK; Centre for Cognitive Neuroimaging, University of Glasgow, Glasgow G12 8QB, UK.
| | - Marios G Philiastides
- School of Psychology and Neuroscience, University of Glasgow, Glasgow G12 8QB, UK; Centre for Cognitive Neuroimaging, University of Glasgow, Glasgow G12 8QB, UK.
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3
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Jepma M, Roy M, Ramlakhan K, van Velzen M, Dahan A. Different brain systems support learning from received and avoided pain during human pain-avoidance learning. eLife 2022; 11:74149. [PMID: 35731646 PMCID: PMC9217130 DOI: 10.7554/elife.74149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 06/07/2022] [Indexed: 12/14/2022] Open
Abstract
Both unexpected pain and unexpected pain absence can drive avoidance learning, but whether they do so via shared or separate neural and neurochemical systems is largely unknown. To address this issue, we combined an instrumental pain-avoidance learning task with computational modeling, functional magnetic resonance imaging (fMRI), and pharmacological manipulations of the dopaminergic (100 mg levodopa) and opioidergic (50 mg naltrexone) systems (N = 83). Computational modeling provided evidence that untreated participants learned more from received than avoided pain. Our dopamine and opioid manipulations negated this learning asymmetry by selectively increasing learning rates for avoided pain. Furthermore, our fMRI analyses revealed that pain prediction errors were encoded in subcortical and limbic brain regions, whereas no-pain prediction errors were encoded in frontal and parietal cortical regions. However, we found no effects of our pharmacological manipulations on the neural encoding of prediction errors. Together, our results suggest that human pain-avoidance learning is supported by separate threat- and safety-learning systems, and that dopamine and endogenous opioids specifically regulate learning from successfully avoided pain.
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Affiliation(s)
- Marieke Jepma
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands.,Department of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden, Netherlands
| | - Mathieu Roy
- Department of Psychology, McGill University, Montreal, Canada.,Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada
| | - Kiran Ramlakhan
- Department of Psychology, Leiden University, Leiden, Netherlands.,Department of Research and Statistics, Municipality of Amsterdam, Amsterdam, Netherlands
| | - Monique van Velzen
- Department of Anesthesiology, Leiden University Medical Center, Leiden, Netherlands
| | - Albert Dahan
- Department of Anesthesiology, Leiden University Medical Center, Leiden, Netherlands
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4
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Armand S, Ozenne B, Svart N, Frøkjaer VG, Knudsen GM, Fisher PM, Stenbaek DS. Brain serotonin transporter is associated with cognitive-affective biases in healthy individuals. Hum Brain Mapp 2022; 43:4174-4184. [PMID: 35607850 PMCID: PMC9374883 DOI: 10.1002/hbm.25946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/21/2022] [Accepted: 05/02/2022] [Indexed: 12/26/2022] Open
Abstract
Cognitive affective biases describe the tendency to process negative information or positive information over the other. These biases can be modulated by changing extracellular serotonin (5-HT) levels in the brain, for example, by pharmacologically blocking and downregulating the 5-HT transporter (5-HTT), which remediates negative affective bias. This suggests that higher levels of 5-HTT are linked to a priority of negative information over positive, but this link remains to be tested in vivo in healthy individuals. We, therefore, evaluated the association between 5-HTT levels, as measured with [11 C]DASB positron emission tomography (PET), and affective biases, hypothesising that higher 5-HTT levels are associated with a more negative bias. We included 98 healthy individuals with measures of [11 C]DASB binding potential (BPND ) and affective biases using The Emotional Faces Identification Task by subtracting the per cent hit rate for happy from that of sad faces (EFITAB ). We evaluated the association between [11 C]DASB BPND and EFITAB in a linear latent variable model, with the latent variable (5-HTTLV ) modelled from [11 C]DASB BPND in the fronto-striatal and fronto-limbic networks implicated in affective cognition. We observed an inverse association between 5-HTTLV and EFITAB (β = -8% EFITAB per unit 5-HTTLV , CI = -14% to -3%, p = .002). These findings show that higher 5-HTT levels are linked to a more negative bias in healthy individuals. High 5-HTT supposedly leads to high clearance of 5-HT, and thus, a negative bias could result from low extracellular 5-HT. Future studies must reveal if a similar inverse association exists in individuals with affective disorders.
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Affiliation(s)
- Sophia Armand
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Brice Ozenne
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Public Health, Section of Biostatistics, University of Copenhagen, Copenhagen, Denmark.,BrainDrugs, Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Nanna Svart
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Vibe G Frøkjaer
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Psychiatric Center Copenhagen, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Patrick M Fisher
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Dea S Stenbaek
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Psychology, University of Copenhagen, Copenhagen, Denmark.,BrainDrugs, Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
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5
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Cools R, Tichelaar JG, Helmich RCG, Bloem BR, Esselink RAJ, Smulders K, Timmer MHM. Role of dopamine and clinical heterogeneity in cognitive dysfunction in Parkinson's disease. PROGRESS IN BRAIN RESEARCH 2022; 269:309-343. [PMID: 35248200 DOI: 10.1016/bs.pbr.2022.01.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Parkinson's disease (PD) is commonly treated with dopaminergic medication, which enhances some, while impairing other cognitive functions. It can even contribute to impulse control disorder and addiction. We describe the history of research supporting the dopamine overdose hypothesis, which accounts for the large within-patient variability in dopaminergic medication effects across different tasks by referring to the spatially non-uniform pattern of dopamine depletion in dorsal versus ventral striatum. However, there is tremendous variability in dopaminergic medication effects not just within patients across distinct tasks, but also across different patients. In the second part of this chapter we review recent studies addressing the large individual variability in the negative side effects of dopaminergic medication on functions that implicate dopamine, such as value-based learning and choice. These studies begin to unravel the mechanisms of dopamine overdosing, thus revising the strict version of the overdose hypothesis. For example, the work shows that the canonical boosting of reward-versus punishment-based choice by medication is greater in patients with depression and a non-tremor phenotype, which both implicate, among other pathology, more rather than less severe dysregulation of the mesolimbic dopamine system. Future longitudinal cohort studies are needed to identify how to optimally combine different clinical, personality, cognitive, neural, genetic and molecular predictors of detrimental medication effects in order to account for as much of the relevant variability as possible. This will provide a useful tool for precision neurology, allowing individual and contextual tailoring of (the dose of) dopaminergic medication in order to maximize its cognitive benefits, yet minimize its side effects.
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Affiliation(s)
- Roshan Cools
- Radboud university medical center, Department of Psychiatry, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
| | - Jorryt G Tichelaar
- Radboud university medical center, Department of Neurology, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Rick C G Helmich
- Radboud university medical center, Department of Neurology, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Bastiaan R Bloem
- Radboud university medical center, Department of Neurology, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Rianne A J Esselink
- Radboud university medical center, Department of Neurology, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Katrijn Smulders
- Radboud university medical center, Department of Neurology, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Monique H M Timmer
- Radboud university medical center, Department of Neurology, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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6
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van Eijndhoven P, Collard R, Vrijsen J, Geurts DEM, Vasquez AA, Schellekens A, van den Munckhof E, Brolsma S, Duyser F, Bergman A, van Oort J, Tendolkar I, Schene A. Measuring Integrated Novel Dimensions in Neurodevelopmental and Stress-Related Mental Disorders (MIND-SET): Protocol for a Cross-sectional Comorbidity Study From a Research Domain Criteria Perspective. JMIRX MED 2022; 3:e31269. [PMID: 37725542 PMCID: PMC10414459 DOI: 10.2196/31269] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/13/2021] [Accepted: 12/06/2021] [Indexed: 09/21/2023]
Abstract
BACKGROUND It is widely acknowledged that comorbidity between psychiatric disorders is common. Shared and diverse underpinnings of psychiatric disorders cannot be systematically understood based on symptom-based categories of mental disorders, which map poorly onto pathophysiological mechanisms. In the Measuring Integrated Novel Dimensions in Neurodevelopmental and Stress-Related Mental Disorders (MIND-SET) study, we make use of current concepts of comorbidity that transcend the current diagnostic categories. We test this approach to psychiatric problems in patients with frequently occurring psychiatric disorders and their comorbidities (excluding psychosis). OBJECTIVE The main aim of the MIND-SET project is to determine the shared and specific mechanisms of neurodevelopmental and stress-related psychiatric disorders at different observational levels. METHODS This is an observational cross-sectional study. Data from different observational levels as defined in the Research Domain Criteria (genetics, physiology, neuropsychology, system-level neuroimaging, behavior, self-report, and experimental neurocognitive paradigms) are collected over four time points. Included are adult (aged ≥18 years), nonpsychotic, psychiatric patients with a clinical diagnosis of a stress-related disorder (mood disorder, anxiety disorder, or substance use disorder) or a neurodevelopmental disorder (autism spectrum disorder or attention-deficit/hyperactivity disorder). Individuals with no current or past psychiatric diagnosis are included as neurotypical controls. Data collection started in June 2016 with the aim to include a total of 650 patients and 150 neurotypical controls by 2021. The data collection procedure includes online questionnaires and three subsequent sessions with (1) standardized clinical examination, physical examination, and blood sampling; (2) psychological constructs, neuropsychological tests, and biological marker sampling; and (3) neuroimaging measures. RESULTS We aim to include a total of 650 patients and 150 neurotypical control participants in the time period between 2016 and 2022. In October 2021, we are at 95% of our target. CONCLUSIONS The MIND-SET study enables us to investigate the mechanistic underpinnings of nonpsychotic psychiatric disorders transdiagnostically. We will identify both shared and disorder-specific markers at different observational levels that can be used as targets for future diagnostic and treatment approaches.
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Affiliation(s)
- Philip van Eijndhoven
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Rose Collard
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Janna Vrijsen
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
- Pro Persona Mental Health Care, Depression Expertise Centre, Nijmegen, Netherlands
| | - Dirk E M Geurts
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Alejandro Arias Vasquez
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Arnt Schellekens
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
- Nijmegen Institute of Scientist-Practitioners in Addiction, Radboud University, Nijmegen, Netherlands
| | - Eva van den Munckhof
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Sophie Brolsma
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Fleur Duyser
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Annemiek Bergman
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Jasper van Oort
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Indira Tendolkar
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
- LVR-Klinikum Essen, Department of Psychiatry and Psychotherapy, University Hospital Essen, Essen, Germany
| | - Aart Schene
- Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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7
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Noworyta K, Cieslik A, Rygula R. Neuromolecular Underpinnings of Negative Cognitive Bias in Depression. Cells 2021; 10:cells10113157. [PMID: 34831380 PMCID: PMC8621066 DOI: 10.3390/cells10113157] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 02/06/2023] Open
Abstract
This selective review aims to summarize the recent advances in understanding the neuromolecular underpinnings of biased cognition in depressive disorder. We begin by considering the cognitive correlates of depressed mood and the key brain systems implicated in its development. We then review the core findings across two domains of biased cognitive function in depression: pessimistic judgment bias and abnormal response to negative feedback. In considering their underlying substrates, we focus on the neurochemical mechanisms identified by genetic, molecular and pharmacological challenge studies. We conclude by discussing experimental approaches to the treatment of depression, which are derived largely from an improved understanding of its cognitive substrates.
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8
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Noworyta K, Rygula R. Phenotypes of reinforcement sensitivity as predictors of the response to acute antidepressant treatment in rats. Eur Neuropsychopharmacol 2021; 43:102-115. [PMID: 33413909 DOI: 10.1016/j.euroneuro.2020.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/03/2020] [Accepted: 12/15/2020] [Indexed: 01/10/2023]
Abstract
One of the biggest threats to modern societies is the increasing prevalence of mood disorders. Cognitive deficits associated with depressive and bipolar disorders are a major driver of functional impairment and the ensuing disability of the suffering individuals. Growing evidence has indicated strong inter-individual differences in the vulnerability to development and effectivity of treatment of these psychiatric conditions, linking various levels of reinforcement sensitivity with specific mood conditions. In this study, we took a unique opportunity to investigate how trait sensitivity to reinforcement determines the reactivity of rats to acute antidepressant treatment. For this, using a preclinical version of the probabilistic reversal-learning (PRL) paradigm, we identified 4 phenotypes of sensitivity to negative and positive feedback in rats, which could represent various types of potential vulnerability to affective disorders. Subsequently, using the light/dark box (LDB) and progressive ratio schedule of reinforcement (PRSR) tests, we evaluated inter-phenotypic differences in the effects of acute treatment with 3 different antidepressant drugs (escitalopram, mirtazapine and clomipramine, each in 3 doses) on anxiety and appetitive motivation of experimental animals. We report statistically significant differences between the investigated phenotypes of reinforcement sensitivity in the effects of acute escitalopram treatment on anxiety in the LDB test. We also report phenotype-independent effects of mirtazapine on motivation and anxiety and a lack of effect of clomipramine. These results demonstrate for the first time that trait sensitivity to reinforcement could have important implications for the effectiveness of treatment in affective disorders.
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Affiliation(s)
- Karolina Noworyta
- Maj Institute of Pharmacology Polish Academy of Sciences, Department of Pharmacology, Affective Cognitive Neuroscience Laboratory, 12 Smetna Street, 31-343 Krakow, Poland
| | - Rafal Rygula
- Maj Institute of Pharmacology Polish Academy of Sciences, Department of Pharmacology, Affective Cognitive Neuroscience Laboratory, 12 Smetna Street, 31-343 Krakow, Poland.
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9
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Serotonin depletion impairs both Pavlovian and instrumental reversal learning in healthy humans. Mol Psychiatry 2021; 26:7200-7210. [PMID: 34429517 PMCID: PMC8873011 DOI: 10.1038/s41380-021-01240-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/03/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023]
Abstract
Serotonin is involved in updating responses to changing environmental circumstances. Optimising behaviour to maximise reward and minimise punishment may require shifting strategies upon encountering new situations. Likewise, autonomic responses to threats are critical for survival yet must be modified as danger shifts from one source to another. Whilst numerous psychiatric disorders are characterised by behavioural and autonomic inflexibility, few studies have examined the contribution of serotonin in humans. We modelled both processes, respectively, in two independent experiments (N = 97). Experiment 1 assessed instrumental (stimulus-response-outcome) reversal learning whereby individuals learned through trial and error which action was most optimal for obtaining reward or avoiding punishment initially, and the contingencies subsequently reversed serially. Experiment 2 examined Pavlovian (stimulus-outcome) reversal learning assessed by the skin conductance response: one innately threatening stimulus predicted receipt of an uncomfortable electric shock and another did not; these contingencies swapped in a reversal phase. Upon depleting the serotonin precursor tryptophan-in a double-blind randomised placebo-controlled design-healthy volunteers showed impairments in updating both actions and autonomic responses to reflect changing contingencies. Reversal deficits in each domain, furthermore, were correlated with the extent of tryptophan depletion. Initial Pavlovian conditioning, moreover, which involved innately threatening stimuli, was potentiated by depletion. These results translate findings in experimental animals to humans and have implications for the neurochemical basis of cognitive inflexibility.
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10
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Aquili L. The Role of Tryptophan and Tyrosine in Executive Function and Reward Processing. Int J Tryptophan Res 2020; 13:1178646920964825. [PMID: 33149600 PMCID: PMC7586026 DOI: 10.1177/1178646920964825] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/10/2020] [Indexed: 01/31/2023] Open
Abstract
The serotonergic precursor tryptophan and the dopaminergic precursor tyrosine have been shown to be important modulators of mood, behaviour and cognition. Specifically, research on the function of tryptophan has characterised this molecule as particularly relevant in the context of pathological disorders such as depression. Moreover, a large body of evidence has now been accumulated to suggest that tryptophan may also be involved in executive function and reward processing. Despite some clear differentiation with tryptophan, the data reviewed in this paper illustrates that tyrosine shares similar functions with tryptophan in the regulation of executive function and reward, and that these processes in turn, rather than acting in isolation, causally influence each other.
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Affiliation(s)
- Luca Aquili
- College of Health & Human Sciences, Charles Darwin University, Darwin, Northern Territory, Australia
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11
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Zhang L, Yu F, Hu Q, Qiao Y, Xuan R, Ji G, Zhu C, Cai C, Wang K. Effects of SSRI Antidepressants on Attentional Bias toward Emotional Scenes in First-Episode Depressive Patients: Evidence from an Eye-Tracking Study. Psychiatry Investig 2020; 17:871-879. [PMID: 32933239 PMCID: PMC7538251 DOI: 10.30773/pi.2019.0345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/07/2020] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Attentional biases toward emotional scenes may represent vulnerability and maintenance factors in depression. Antidepressant therapy may improve cognitive function and reduce depression, and is considered as the mechanism of action of antidepressants. Therefore, we conducted an eye-tracking test to examine whether selective serotonin re-uptake inhibitor (SSRI) antidepressants can reduce negative attentional biases and elicit clinical responses in depression. METHODS Twenty first-episode depressive patients freely viewed three types of pictures that depicted different emotional scenes (i.e., positive-control, neutral-control, and negative-control) for 4,000 ms while their eye movements were monitored. The attentional bias to different emotional scenes was assessed before and after eight weeks of SSRI treatment using the eye-tracking method. The control group included a group of healthy individuals. RESULTS The results revealed that first-episode depressive patients oriented their gaze more frequently to negative images and less to happy images, compared to controls. Importantly, the attentional bias in depressive patients was regulated after eight weeks of SSRI treatment. Patients showed an increased tendency to fixate on positive images and a decreased tendency to focus on negative images. CONCLUSION This suggests that SSRI antidepressants decrease vulnerability to negative images, while having an effect on attention in respect to positive images.
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Affiliation(s)
- Lei Zhang
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | - Fengqiong Yu
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | - Qian Hu
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | - Yuxi Qiao
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | - Rongrong Xuan
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | - Gongjun Ji
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | - Chunyan Zhu
- Department of Medical Psychology, Chaohu Clinical Medical College, Anhui Medical University, Hefei, China.,Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
| | | | - Kai Wang
- Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China.,Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.,Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China
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12
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Effects of serotonin and dopamine depletion on neural prediction computations during social learning. Neuropsychopharmacology 2020; 45:1431-1437. [PMID: 32330925 PMCID: PMC7360591 DOI: 10.1038/s41386-020-0678-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 01/23/2023]
Abstract
We have previously shown that individuals with high depression scores demonstrate impaired behavioral and neural responses during social learning. Given that depression is associated with altered dopamine (DA) and serotonin (5-HT) functioning, the current study aimed to elucidate the role of these neurotransmitters in the social learning process using a dietary depletion manipulation. In a double-blind design, 70 healthy volunteers were randomly allocated to a 5-HT depletion (N = 24), DA depletion (N = 24), or placebo (N = 22) group. Participants performed a social learning task during fMRI scanning, as part of which they learned associations between name cues and rewarding (happy faces) or aversive (fearful faces) social outcomes. Behaviorally, 5-HT depleted subjects demonstrated impaired social reward learning compared to placebo controls, with a marginal effect in the same direction in the DA depletion group. On the neural level, computational modeling-based fMRI analyses revealed that 5-HT depletion altered social reward prediction signals in the insula, temporal lobe, and prefrontal cortex, while DA depletion affected social reward prediction encoding only in the prefrontal cortex. These results indicate that 5-HT depletion impairs learning from social rewards, on both the behavioral and the neural level, while DA depletion has a less extensive effect. Interestingly, the behavioral and neural responses observed after 5-HT depletion in the current study closely resemble our previous findings in individuals with high depression scores using the same task. It may thus be the case that decreased 5-HT levels contribute to social learning deficits in depression.
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13
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Thirkettle M, Barker LM, Gallagher T, Nayeb N, Aquili L. Dissociable Effects of Tryptophan Supplementation on Negative Feedback Sensitivity and Reversal Learning. Front Behav Neurosci 2019; 13:127. [PMID: 31316358 PMCID: PMC6609902 DOI: 10.3389/fnbeh.2019.00127] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/28/2019] [Indexed: 11/24/2022] Open
Abstract
Serotonin has been shown to modulate probabilistic reversal learning (PRL) and negative feedback sensitivity (NFS) in both animal and human studies. Whilst these two measures are tightly coupled, some studies have suggested that these may be mediated by independent mechanisms; the former, representing perseveration and cognitive flexibility, and the latter measuring the ability to maintain a response set (win-stay) at the expense of lose-shift behavior when occasional misleading feedback has been presented. Here, we tested this hypothesis in 44 healthy participants who were administered tryptophan (22 placebo, 22 tryptophan), a precursor to serotonin. We found a dissociable effect of tryptophan supplementation on PRL/NFS. Specifically, tryptophan administration increased NFS compared to the placebo group but had no effect on PRL. We discuss these findings in relation to dosages and with a particular focus on the acute tryptophan depletion (ATD) procedures.
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Affiliation(s)
- Martin Thirkettle
- Department of Psychology, Sociology and Politics, Sheffield Hallam University, Sheffield, United Kingdom
| | - Laura-Marie Barker
- Department of Psychology, Sociology and Politics, Sheffield Hallam University, Sheffield, United Kingdom
| | - Thomas Gallagher
- Department of Psychology, Sociology and Politics, Sheffield Hallam University, Sheffield, United Kingdom
| | - Nazgol Nayeb
- Department of Psychology, Sociology and Politics, Sheffield Hallam University, Sheffield, United Kingdom
| | - Luca Aquili
- Department of Psychology, Sociology and Politics, Sheffield Hallam University, Sheffield, United Kingdom
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14
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Rygula R, Noworyta-Sokolowska K, Drozd R, Kozub A. Using rodents to model abnormal sensitivity to feedback in depression. Neurosci Biobehav Rev 2018; 95:336-346. [DOI: 10.1016/j.neubiorev.2018.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/16/2018] [Accepted: 10/16/2018] [Indexed: 11/30/2022]
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15
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Gu S, Gao M, Yan Y, Wang F, Tang YY, Huang JH. The Neural Mechanism Underlying Cognitive and Emotional Processes in Creativity. Front Psychol 2018; 9:1924. [PMID: 30429805 PMCID: PMC6220028 DOI: 10.3389/fpsyg.2018.01924] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 09/19/2018] [Indexed: 12/16/2022] Open
Abstract
Creativity is related to both cognition and emotion, which are the two major mental processes, interacting with each other to form psychological processes. Emotion is the major driving force of almost all creativities, sometimes in an unconscious way. Even though there are many studies concerning the relationship between creativity and cognition, there are few studies about the neural mechanisms of the emotional effects on creativity. Here, we introduce a novel model to explain the relationship between emotions and creativities: Three Primary Color model, which proposes that there are four major basic emotions; these basic emotions are subsided by three monoamines, just like the three primary colors: dopamine-joy, norepinephrine-stress (fear and anger), and serotonin-punishment. Interestingly, these three neuromodulators play similar roles in creativity, whose core features are value and novelty (surprise), like the characteristics of the core features of basic emotions (hedonic value and arousal value). Dysfunctions of these neuromodulators may be the reasons for both psychopathology and creativity, in that they can change the thinking styles such as novelty seeking behavior, hyper-connectivity of brain areas, and/or cognitive disinhibition to induce both creativity and psychopathology. This new model will not only help researchers understand the dynamics of basic emotion elements, it can also bring an entirely new perspective into the relationship between psychopathology and creativity.
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Affiliation(s)
- Simeng Gu
- Department of Psychology, School of Medicine, Jiangsu University, Zhenjiang, China.,Institute of Emotion, School of Psychology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Mengdan Gao
- Institute of Emotion, School of Psychology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yaoyao Yan
- Institute of Emotion, School of Psychology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Fushun Wang
- Institute of Emotion, School of Psychology, Nanjing University of Chinese Medicine, Nanjing, China.,Department of Neurosurgery, Baylor Scott & White Health, Temple, TX, United States.,College of Medicine, Texas A&M HSC, Temple, TX, United States
| | - Yi-Yuan Tang
- Department of Psychological Sciences, Texas Tech University, Lubbock, TX, United States.,Center for Advanced Study in the Behavioral Sciences, Stanford University, Stanford, CA, United States
| | - Jason H Huang
- Department of Neurosurgery, Baylor Scott & White Health, Temple, TX, United States.,College of Medicine, Texas A&M HSC, Temple, TX, United States
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16
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Carlisi CO, Robinson OJ. The role of prefrontal-subcortical circuitry in negative bias in anxiety: Translational, developmental and treatment perspectives. Brain Neurosci Adv 2018; 2:2398212818774223. [PMID: 30167466 PMCID: PMC6097108 DOI: 10.1177/2398212818774223] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/09/2018] [Indexed: 12/22/2022] Open
Abstract
Anxiety disorders are the most common cause of mental ill health in the developed world, but our understanding of symptoms and treatments is not presently grounded in knowledge of the underlying neurobiological mechanisms. In this review, we discuss accumulating work that points to a role for prefrontal-subcortical brain circuitry in driving a core psychological symptom of anxiety disorders - negative affective bias. Specifically, we point to converging work across humans and animal models, suggesting a reciprocal relationship between dorsal and ventral prefrontal-amygdala circuits in promoting and inhibiting negative bias, respectively. We discuss how the developmental trajectory of these circuits may lead to the onset of anxiety during adolescence and, moreover, how effective pharmacological and psychological treatments may serve to shift the balance of activity within this circuitry to ameliorate negative bias symptoms. Together, these findings may bring us closer to a mechanistic, neurobiological understanding of anxiety disorders and their treatment.
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Affiliation(s)
- Christina O. Carlisi
- Division of Psychology and Language Sciences, University College London, London, UK
| | - Oliver J. Robinson
- Institute of Cognitive Neuroscience, University College London, London, UK
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17
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Fischer AG, Ullsperger M. An Update on the Role of Serotonin and its Interplay with Dopamine for Reward. Front Hum Neurosci 2017; 11:484. [PMID: 29075184 PMCID: PMC5641585 DOI: 10.3389/fnhum.2017.00484] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/19/2017] [Indexed: 01/02/2023] Open
Abstract
The specific role of serotonin and its interplay with dopamine (DA) in adaptive, reward guided behavior as well as drug dependance, still remains elusive. Recently, novel methods allowed cell type specific anatomical, functional and interventional analyses of serotonergic and dopaminergic circuits, promising significant advancement in understanding their functional roles. Furthermore, it is increasingly recognized that co-release of neurotransmitters is functionally relevant, understanding of which is required in order to interpret results of pharmacological studies and their relationship to neural recordings. Here, we review recent animal studies employing such techniques with the aim to connect their results to effects observed in human pharmacological studies and subjective effects of drugs. It appears that the additive effect of serotonin and DA conveys significant reward related information and is subjectively highly euphorizing. Neither DA nor serotonin alone have such an effect. This coincides with optogenetically targeted recordings in mice, where the dopaminergic system codes reward prediction errors (PE), and the serotonergic system mainly unsigned PE. Overall, this pattern of results indicates that joint activity between both systems carries essential reward information and invites parallel investigation of both neurotransmitter systems.
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Affiliation(s)
- Adrian G Fischer
- Department of Neuropsychology, Institute of Psychology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Markus Ullsperger
- Department of Neuropsychology, Institute of Psychology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
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18
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Timmer MHM, Sescousse G, van der Schaaf ME, Esselink RAJ, Cools R. Reward learning deficits in Parkinson's disease depend on depression. Psychol Med 2017; 47:2302-2311. [PMID: 28374660 DOI: 10.1017/s0033291717000769] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Depression is one of the most common and debilitating non-motor symptoms of Parkinson's disease (PD). The neurocognitive mechanisms underlying depression in PD are unclear and treatment is often suboptimal. METHODS We investigated the role of striatal dopamine in reversal learning from reward and punishment by combining a controlled medication withdrawal procedure with functional magnetic resonance imaging in 22 non-depressed PD patients and 19 PD patients with past or present depression. RESULTS PD patients with a depression (history) exhibited impaired reward v. punishment reversal learning as well as reduced reward v. punishment-related BOLD signal in the striatum (putamen) compared with non-depressed PD patients. No effects of dopaminergic medication were observed. CONCLUSIONS The present findings demonstrate that impairments in reversal learning from reward v. punishment and associated striatal signalling depend on the presence of (a history of) depression in PD.
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Affiliation(s)
- M H M Timmer
- Donders Institute for Brain,Cognition and Behaviour,Centre for Cognitive Neuroimaging,Radboud University,Nijmegen,The Netherlands
| | - G Sescousse
- Donders Institute for Brain,Cognition and Behaviour,Centre for Cognitive Neuroimaging,Radboud University,Nijmegen,The Netherlands
| | - M E van der Schaaf
- Donders Institute for Brain,Cognition and Behaviour,Centre for Cognitive Neuroimaging,Radboud University,Nijmegen,The Netherlands
| | - R A J Esselink
- Department of Neurology and Parkinson Center Nijmegen (ParC),Radboud University Medical Center,Nijmegen,The Netherlands
| | - R Cools
- Donders Institute for Brain,Cognition and Behaviour,Centre for Cognitive Neuroimaging,Radboud University,Nijmegen,The Netherlands
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19
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Wong-Lin K, Wang DH, Moustafa AA, Cohen JY, Nakamura K. Toward a multiscale modeling framework for understanding serotonergic function. J Psychopharmacol 2017; 31:1121-1136. [PMID: 28417684 PMCID: PMC5606304 DOI: 10.1177/0269881117699612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Despite its importance in regulating emotion and mental wellbeing, the complex structure and function of the serotonergic system present formidable challenges toward understanding its mechanisms. In this paper, we review studies investigating the interactions between serotonergic and related brain systems and their behavior at multiple scales, with a focus on biologically-based computational modeling. We first discuss serotonergic intracellular signaling and neuronal excitability, followed by neuronal circuit and systems levels. At each level of organization, we will discuss the experimental work accompanied by related computational modeling work. We then suggest that a multiscale modeling approach that integrates the various levels of neurobiological organization could potentially transform the way we understand the complex functions associated with serotonin.
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Affiliation(s)
- KongFatt Wong-Lin
- Intelligent Systems Research Centre, School of Computing and Intelligent Systems, University of Ulster, Magee Campus, Derry~Londonderry, UK
| | - Da-Hui Wang
- School of Systems Science, and National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Ahmed A Moustafa
- School of Social Sciences and Psychology, and Marcs Institute for Brain and Behaviour, University of Western Sydney, Sydney, Australia
| | - Jeremiah Y Cohen
- Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Kae Nakamura
- Department of Physiology, Kansai Medical University, Hirakata, Osaka, Japan
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20
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Enge S, Mothes H, Fleischhauer M, Reif A, Strobel A. Genetic variation of dopamine and serotonin function modulates the feedback-related negativity during altruistic punishment. Sci Rep 2017; 7:2996. [PMID: 28592831 PMCID: PMC5462809 DOI: 10.1038/s41598-017-02594-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/12/2017] [Indexed: 12/16/2022] Open
Abstract
Why do humans cooperate and often punish norm violations of others? In the present study, we sought to investigate the genetic bases of altruistic punishment (AP), which refers to the costly punishment of norm violations with potential benefit for other individuals. Recent evidence suggests that norm violations and unfairness are indexed by the feedback-related negativity (FRN), an anterior cingulate cortex (ACC) generated neural response to expectancy violations. Given evidence on the role of serotonin and dopamine in AP as well as in FRN-generation, we explored the impact of genetic variation of serotonin and dopamine function on FRN and AP behavior in response to unfair vs. fair monetary offers in a Dictator Game (DG) with punishment option. In a sample of 45 healthy participants we observed larger FRN amplitudes to unfair DG assignments both for 7-repeat allele carriers of the dopamine D4 receptor (DRD4) exon III polymorphism and for l/l-genotype carriers of the serotonin transporter gene-linked polymorphic region (5-HTTLRP). Moreover, 5-HTTLPR l/l-genotype carriers punished unfair offers more strongly. These findings support the role of serotonin and dopamine in AP, potentially via their influence on neural mechanisms implicated in the monitoring of expectancy violations and their relation to impulsive and punishment behavior.
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Affiliation(s)
- Sören Enge
- Department of Psychology, Faculty of Natural Sciences, MSB Medical School Berlin, Berlin, Germany. .,Department of Psychology, Technische Universität Dresden, Dresden, Germany.
| | - Hendrik Mothes
- Department of Sports Science, University of Freiburg, Freiburg, Germany
| | - Monika Fleischhauer
- Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.,PFH Private Hochschule Göttingen, Göttingen, Germany
| | - Andreas Reif
- Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt/Main, Frankfurt/Main, Germany
| | - Alexander Strobel
- Department of Psychology, Technische Universität Dresden, Dresden, Germany
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21
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Kavoor AR, Mitra S, Kumar S, Sisodia AK, Jain R. Lipids, aggression, suicidality and impulsivity in drug-naïve/drug-free patients of schizophrenia. Asian J Psychiatr 2017; 27:129-136. [PMID: 28558886 DOI: 10.1016/j.ajp.2017.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 02/13/2017] [Accepted: 03/01/2017] [Indexed: 12/25/2022]
Abstract
AIM Present study aimed at determining lipid profiles in acutely symptomatic drug-naïve/drug-free patients of schizophrenia, comparing them with healthy controls and exploring relationships between various lipid fractions, aggression, suicidality and impulsivity in this population. MATERIALS AND METHODS This was a cross-sectional hospital-based study, comparing patients with schizophrenia (M=46, F=14; mean age 32.40±6.6 years; 48 drug-free for 10.50±9.2 weeks) with 60 age-sex matched healthy controls. Upon recruitment, fasting venous blood samples of all subjects were analysed for total cholesterol, HDL, LDL, VLDL and TG levels, and patients were rated on PANSS for symptom severity, Modified Overt Aggression Scale for aggression, Impulsivity Rating Scale for impulsivity and Scale for Suicide Ideation for suicidality. RESULTS The socio-demographic characteristics of the patients were comparable to controls. In patients, total cholesterol, HDL and LDL levels were found to be significantly lower (p<0.01) than the control group. When explored further in patients, lower total cholesterol and LDL levels showed significant negative correlations with scores on impulsivity (p<0.01) and suicidality (p<0.05); and TG level showed a negative correlation with impulsivity (p<0.05). CONCLUSIONS This study adds to a growing literature on a complex relationship between lipid fractions and impulsivity, suicidality and aggression in schizophrenia; providing interesting insights into the biochemical basis of human behaviour and confirming these in a developing-world population. The implications are many, including a need to review judiciously the promotion of weight loss and cholesterol reduction programmes in constitutionally vulnerable population, at least during their acutely-symptomatic states.
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Affiliation(s)
| | | | - Sudhir Kumar
- Institute of Mental Health and Hospital, Agra, Uttar Pradesh, India
| | - Anil Kr Sisodia
- Institute of Mental Health and Hospital, Agra, Uttar Pradesh, India
| | - Rakesh Jain
- Institute of Mental Health and Hospital, Agra, Uttar Pradesh, India
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22
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Beyond negative valence: 2-week administration of a serotonergic antidepressant enhances both reward and effort learning signals. PLoS Biol 2017; 15:e2000756. [PMID: 28207733 PMCID: PMC5331946 DOI: 10.1371/journal.pbio.2000756] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 01/19/2017] [Indexed: 12/21/2022] Open
Abstract
To make good decisions, humans need to learn about and integrate different sources of appetitive and aversive information. While serotonin has been linked to value-based decision-making, its role in learning is less clear, with acute manipulations often producing inconsistent results. Here, we show that when the effects of a selective serotonin reuptake inhibitor (SSRI, citalopram) are studied over longer timescales, learning is robustly improved. We measured brain activity with functional magnetic resonance imaging (fMRI) in volunteers as they performed a concurrent appetitive (money) and aversive (effort) learning task. We found that 2 weeks of citalopram enhanced reward and effort learning signals in a widespread network of brain regions, including ventromedial prefrontal and anterior cingulate cortex. At a behavioral level, this was accompanied by more robust reward learning. This suggests that serotonin can modulate the ability to learn via a mechanism that is independent of stimulus valence. Such effects may partly underlie SSRIs’ impact in treating psychological illnesses. Our results highlight both a specific function in learning for serotonin and the importance of studying its role across longer timescales. Drugs acting on the neurotransmitter serotonin in the brain are commonly prescribed to treat depression, but we still lack a complete understanding of their effects on the brain and behavior. We do, however, know that patients who suffer from depression learn about the links between their choices and pleasant and unpleasant outcomes in a different manner than healthy controls. Neural markers of learning are also weakened in depressed people. Here, we looked at the effects of a short-term course (2 weeks) of a serotonergic antidepressant on brain and behavior in healthy volunteers while they learnt to predict what consequences their choices had in a simple computer task. We found that the antidepressant increased how strongly brain areas concerned with predictions of pleasant and unpleasant consequences became active during learning of the task. At the same time, participants who had taken the antidepressant also performed better on the task. Our results suggest that serotonergic drugs might exert their beneficial clinical effects by changing how the brain learns.
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23
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Abstract
INTRODUCTION Although there is clear evidence for the serotonergic regulation of descending control of pain in animals, little direct evidence exists in humans. The majority of our knowledge comes from the use of serotonin (5-HT)-modulating antidepressants as analgesics in the clinical management of chronic pain. OBJECTIVES Here, we have used an acute tryptophan depletion (ATD) to manipulate 5-HT function and examine its effects of ATD on heat pain threshold and tolerance, attentional manipulation of nociceptive processing and mood in human volunteers. METHODS Fifteen healthy participants received both ATD and balanced amino acid (BAL) drinks on two separate sessions in a double-blind cross-over design. Pain threshold and tolerance were determined 4 h post-drink via a heat thermode. Additional attention, distraction and temperature discrimination paradigms were completed using a laser-induced heat pain stimulus. Mood was assessed prior and throughout each session. RESULTS Our investigation reported that the ATD lowered plasma TRP levels by 65.05 ± 7.29% and significantly reduced pain threshold and tolerance in response to the heat thermode. There was a direct correlation between the reduction in total plasma TRP levels and reduction in thermode temperature. In contrast, ATD showed no effect on laser-induced pain nor significant impact of the distraction-induced analgesia on pain perception but did reduce performance of the painful temperature discrimination task. Importantly, all findings were independent of any effects of ATD on mood. CONCLUSION As far as we are aware, it is the first demonstration of 5-HT effects on pain perception which are not confounded by mood changes.
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Eisner P, Klasen M, Wolf D, Zerres K, Eggermann T, Eisert A, Zvyagintsev M, Sarkheil P, Mathiak KA, Zepf F, Mathiak K. Cortico-limbic connectivity in MAOA-L carriers is vulnerable to acute tryptophan depletion. Hum Brain Mapp 2016; 38:1622-1635. [PMID: 27935229 DOI: 10.1002/hbm.23475] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 01/12/2023] Open
Abstract
INTRODUCTION A gene-environment interaction between expression genotypes of the monoamine oxidase A (MAOA) and adverse childhood experience increases the risk of antisocial behavior. However, the neural underpinnings of this interaction remain uninvestigated. A cortico-limbic circuit involving the prefrontal cortex (PFC) and the amygdala is central to the suppression of aggressive impulses and is modulated by serotonin (5-HT). MAOA genotypes may modulate the vulnerability of this circuit and increase the risk for emotion regulation deficits after specific life events. Acute tryptophan depletion (ATD) challenges 5-HT regulation and may identify vulnerable neuronal circuits, contributing to the gene-environment interaction. METHODS Functional magnetic resonance imaging measured the resting-state state activity in 64 healthy males in a double-blind, placebo-controlled study. Cortical maps of amygdala correlation identified the impact of ATD and its interaction with low- (MAOA-L) and high-expression variants (MAOA-H) of MAOA on cortico-limbic connectivity. RESULTS Across all Regions of Interest (ROIs) exhibiting an ATD effect on cortico-limbic connectivity, MAOA-L carriers were more susceptible to ATD than MAOA-H carriers. In particular, the MAOA-L group exhibited a larger reduction of amygdala connectivity with the right prefrontal cortex and a larger increase of amygdala connectivity with the insula and dorsal PCC. CONCLUSION MAOA-L carriers were more susceptable to a central 5-HT challenge in cortico-limbic networks. Such vulnerability of the cortical serotonergic system may contribute to the emergence of antisocial behavior after systemic challenges, observed as gene-environment interaction. Hum Brain Mapp 38:1622-1635, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Patrick Eisner
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
| | - Martin Klasen
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
| | - Dhana Wolf
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
| | - Klaus Zerres
- Department of Human Genetics, Medical School, RWTH Aachen University, Aachen, Germany
| | - Thomas Eggermann
- Department of Human Genetics, Medical School, RWTH Aachen University, Aachen, Germany
| | - Albrecht Eisert
- Department of Pharmacy, RWTH Aachen University, Aachen, Germany
| | - Mikhail Zvyagintsev
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
| | - Pegah Sarkheil
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
| | - Krystyna A Mathiak
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
| | - Florian Zepf
- Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences and School of Pediatrics and Child Health; Faculty of Medicine, Dentistry and Health Sciences; The University of Western Australia (M561), Perth, Australia.,Department of Health in Western Australia, Specialized Child and Adolescent Mental Health Services (CAMHS), Perth, Australia
| | - Klaus Mathiak
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany
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25
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Mavrogiorgou P, Enzi B, Klimm AK, Köhler E, Roser P, Norra C, Juckel G. Serotonergic modulation of orbitofrontal activity and its relevance for decision making and impulsivity. Hum Brain Mapp 2016; 38:1507-1517. [PMID: 27862593 DOI: 10.1002/hbm.23468] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 10/25/2016] [Accepted: 11/06/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The orbitofrontal cortex seems to play a crucial role in reward-guided learning and decision making, especially for impulsive choice procedures including delayed reward discounting. The central serotonergic system is closely involved in the regulation of impulsivity, but how the serotonergic firing rate and release, best investigated by the loudness dependence of auditory evoked potentials (LDAEP), interact with orbitofrontal activity is still unknown. METHODS Twenty healthy volunteers (11 males, 9 females, 31.3 ± 10.6 years old) were studied in a 3T MRI scanner (Philips, Hamburg, Germany) during a delay discounting task, after their LDAEP was recorded using a 32 electrodes EEG machine (Brain Products, Munich, Germany). RESULTS Significant positive correlations were only found between the LDAEP and the medial orbitofrontal part of the superior frontal gyrus (SFG/MO) [Δ immediate reward - delayed reward] for the right (r = 0.519; P = 0.019) and left side (r = 0.478; P = 0.033). This relationship was stronger for females compared with males. Orbitofrontal activity was also related to the Barratt Impulsivity Scale. CONCLUSIONS This study revealed that low serotonergic activity as measured by a strong LDAEP was related to a high fMRI signal intensity of SFG/MO during immediate reward behavior which is related to impulsivity. Since this relationship was only found for the infralimbic medial and not for the middle or lateral part of the orbitofrontal cortex, an exclusive projection tract of the serotonergic system to this cortical region can be assumed to regulate impulsive reward-orientated decision making. Hum Brain Mapp 38:1507-1517, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Paraskevi Mavrogiorgou
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
| | - Björn Enzi
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
| | - Ann-Kristin Klimm
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
| | - Elke Köhler
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
| | - Patrik Roser
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
| | - Christine Norra
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
| | - Georg Juckel
- Department of Psychiatry, Ruhr University Bochum, LWL University Hospital, Alexandrinenstr. 1, Bochum, 44791, Germany
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Faulkner P, Mancinelli F, Lockwood PL, Matarin M, Dolan RJ, Wood NW, Dayan P, Roiser JP. Peripheral Serotonin 1B Receptor Transcription Predicts the Effect of Acute Tryptophan Depletion on Risky Decision-Making. Int J Neuropsychopharmacol 2016; 20:58-66. [PMID: 27638901 PMCID: PMC5480594 DOI: 10.1093/ijnp/pyw075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/13/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The effects of acute tryptophan depletion on human decision-making suggest that serotonin modulates the processing of rewards and punishments. However, few studies have assessed which of the many types of serotonin receptors are responsible. METHODS Using a within-subject, double-blind, sham-controlled design in 26 subjects, we examined whether individual differences in serotonin system gene transcription, measured in peripheral blood, predicted the effect of acute tryptophan depletion on decision-making. Participants performed a task in which they chose between successive pairs of fixed, lower-stakes (control) and variable, higher-stakes (experimental) gambles, each involving wins or losses. In 21 participants, mRNA from 9 serotonin system genes was measured in whole blood prior to acute tryptophan depletion: 5-HT1B, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT3A, 5-HT3E, 5-HT7 (serotonin receptors), 5-HTT (the serotonin transporter), and tryptophan hydroxylase 1. RESULTS Acute tryptophan depletion did not significantly influence participants' sensitivity to probability, wins, or losses, although there was a trend for a lower tendency to choose experimental gambles overall following depletion. Significant positive correlations, which survived correction for multiple comparisons, were detected between baseline 5-HT1B mRNA levels and acute tryptophan depletion-induced increases in both the overall tendency to choose the experimental gamble and sensitivity to wins. No significant relationship was observed with any other peripheral serotonin system markers. Computational analyses of decision-making data provided results consistent with these findings. CONCLUSIONS These results suggest that the 5-HT1B receptor may modulate the effects of acute tryptophan depletion on risky decision-making. Peripheral levels of serotonin markers may predict response to treatments that act upon the serotonin system, such as selective serotonin reuptake inhibitors.
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Affiliation(s)
- Paul Faulkner
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner);,Correspondence: Paul Faulkner, PhD, Semel Institute, 760 Westwood Boulevard, University of California, Los Angeles, CA 90025 ()
| | - Federico Mancinelli
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner)
| | - Patricia L Lockwood
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner)
| | - Mar Matarin
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner)
| | - Raymond J Dolan
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner)
| | - Nick W Wood
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner)
| | - Peter Dayan
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom (Drs Faulkner and Roiser); Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California (Dr Faulkner)
| | - Jonathan P Roiser
- Gatsby Computational Neuroscience Unit (Mr Mancinelli and Dr Dayan), and CoMPLEX Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology (Mr Mancinelli), University College London, London, United Kingdom; Experimental Psychology, University of Oxford, Oxford, United Kingdom (Dr Lockwood); Clinical and Experimental Epilepsy, Institute of Neurology (Dr Matarin), and Wellcome Trust Centre for Neuroimaging (Dr Dolan), University College London, London, United Kingdom; Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, United Kingdom (Dr Wood)
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Gillan CM, Robbins TW, Sahakian BJ, van den Heuvel OA, van Wingen G. The role of habit in compulsivity. Eur Neuropsychopharmacol 2016; 26:828-40. [PMID: 26774661 PMCID: PMC4894125 DOI: 10.1016/j.euroneuro.2015.12.033] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 12/17/2015] [Accepted: 12/20/2015] [Indexed: 11/22/2022]
Abstract
Compulsivity has been recently characterized as a manifestation of an imbalance between the brain׳s goal-directed and habit-learning systems. Habits are perhaps the most fundamental building block of animal learning, and it is therefore unsurprising that there are multiple ways in which the development and execution of habits can be promoted/discouraged. Delineating these neurocognitive routes may be critical to understanding if and how habits contribute to the many faces of compulsivity observed across a range of psychiatric disorders. In this review, we distinguish the contribution of excessive stimulus-response habit learning from that of deficient goal-directed control over action and response inhibition, and discuss the role of stress and anxiety as likely contributors to the transition from goal-directed action to habit. To this end, behavioural, pharmacological, neurobiological and clinical evidence are synthesised and a hypothesis is formulated to capture how habits fit into a model of compulsivity as a trans-diagnostic psychiatric trait.
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Affiliation(s)
- Claire M Gillan
- Department of Psychology, New York University, 6 Washington Place, New York, NY 10003, USA; Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom.
| | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Barbara J Sahakian
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Odile A van den Heuvel
- Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands; Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands; The OCD Team, Haukeland University Hospital, Bergen, Norway
| | - Guido van Wingen
- Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Carlisi CO, Chantiluke K, Norman L, Christakou A, Barrett N, Giampietro V, Brammer M, Simmons A, Rubia K. The effects of acute fluoxetine administration on temporal discounting in youth with ADHD. Psychol Med 2016; 46:1197-1209. [PMID: 26708124 DOI: 10.1017/s0033291715002731] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Serotonin is under-researched in attention deficit hyperactivity disorder (ADHD), despite accumulating evidence for its involvement in impulsiveness and the disorder. Serotonin further modulates temporal discounting (TD), which is typically abnormal in ADHD relative to healthy subjects, underpinned by reduced fronto-striato-limbic activation. This study tested whether a single acute dose of the selective serotonin reuptake inhibitor (SSRI) fluoxetine up-regulates and normalizes reduced fronto-striato-limbic neurofunctional activation in ADHD during TD. METHOD Twelve boys with ADHD were scanned twice in a placebo-controlled randomized design under either fluoxetine (between 8 and 15 mg, titrated to weight) or placebo while performing an individually adjusted functional magnetic resonance imaging TD task. Twenty healthy controls were scanned once. Brain activation was compared in patients under either drug condition and compared to controls to test for normalization effects. RESULTS Repeated-measures whole-brain analysis in patients revealed significant up-regulation with fluoxetine in a large cluster comprising right inferior frontal cortex, insula, premotor cortex and basal ganglia, which further correlated trend-wise with TD performance, which was impaired relative to controls under placebo, but normalized under fluoxetine. Fluoxetine further down-regulated default mode areas of posterior cingulate and precuneus. Comparisons between controls and patients under either drug condition revealed normalization with fluoxetine in right premotor-insular-parietal activation, which was reduced in patients under placebo. CONCLUSIONS The findings show that a serotonin agonist up-regulates activation in typical ADHD dysfunctional areas in right inferior frontal cortex, insula and striatum as well as down-regulating default mode network regions in the context of impulsivity and TD.
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Affiliation(s)
- C O Carlisi
- Department of Child & Adolescent Psychiatry,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - K Chantiluke
- Department of Child & Adolescent Psychiatry,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - L Norman
- Department of Child & Adolescent Psychiatry,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - A Christakou
- Department of Child & Adolescent Psychiatry,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - N Barrett
- South London and Maudsley NHS Trust,London,UK
| | - V Giampietro
- Department of Neuroimaging,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - M Brammer
- Department of Neuroimaging,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - A Simmons
- Department of Neuroimaging,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
| | - K Rubia
- Department of Child & Adolescent Psychiatry,Institute of Psychiatry, Psychology and Neuroscience,King's College,London,UK
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29
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Crockett MJ, Cools R. Serotonin and aversive processing in affective and social decision-making. Curr Opin Behav Sci 2015. [DOI: 10.1016/j.cobeha.2015.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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30
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Serotonin reuptake inhibitors and serotonin transporter genotype modulate performance monitoring functions but not their electrophysiological correlates. J Neurosci 2015; 35:8181-90. [PMID: 26019334 DOI: 10.1523/jneurosci.5124-14.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Serotonin (5-HT) has been hypothesized to be implicated in performance monitoring by promoting behavioral inhibition in the face of aversive events. However, it is unclear whether this is restricted to external (punishment) or includes internal (response errors) events. The aim of the current study was to test whether higher 5-HT levels instigate inhibition specifically in the face of errors, measured as post-error slowing (PES), and whether this is represented in electrophysiological correlates of error processing, namely error-related negativity (ERN) and positivity. Therefore, from a large sample of human subjects (n = 878), two extreme groups were formed regarding hypothesized high and low 5-HT transporter (5-HTT) expression based on 5-HTTLPR and two additional single nucleotide polymorphisms (rs25531, rs25532). Seventeen higher (LL) and 15 lower (SS) expressing Caucasian subjects were administered the selective serotonin reuptake inhibitor (SSRI) citalopram (10 mg) intravenously in a double-blind crossover design. We found pharmacogenetic evidence for a role of 5-HT in mediating PES: SSRI administration increased PES in both genetic groups, and SS subjects displayed higher PES. These effects were absent on post-conflict slowing. However, ERN and error positivity were unaffected by pharmacogenetic factors, but ERN was decoupled from behavioral adaptation by SSRI administration in the LL group. Thus, pharmacogenetic evidence suggests that increased 5-HT levels lead to behavioral inhibition in the context of internal aversive events, but electrophysiological correlates of performance monitoring appear unrelated to the 5-HT system. Therefore, our findings are consistent with theories suggesting that 5-HT mediates the link between aversive processing and inhibition.
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31
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Gaber TJ, Dingerkus VLS, Crockett MJ, Bubenzer-Busch S, Helmbold K, Sánchez CL, Dahmen B, Herpertz-Dahlmann B, Zepf FD. Studying the effects of dietary body weight-adjusted acute tryptophan depletion on punishment-related behavioral inhibition. Food Nutr Res 2015; 59:28443. [PMID: 26268708 PMCID: PMC4534625 DOI: 10.3402/fnr.v59.28443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/22/2015] [Accepted: 06/23/2015] [Indexed: 12/15/2022] Open
Abstract
Background Alterations in serotonergic (5-HT) neurotransmission are thought to play a decisive role in affective disorders and impulse control. Objective This study aims to reproduce and extend previous findings on the effects of acute tryptophan depletion (ATD) and subsequently diminished central 5-HT synthesis in a reinforced categorization task using a refined body weight–adjusted depletion protocol. Design Twenty-four young healthy adults (12 females, mean age [SD]=25.3 [2.1] years) were subjected to a double-blind within-subject crossover design. Each subject was administered both an ATD challenge and a balanced amino acid load (BAL) in two separate sessions in randomized order. Punishment-related behavioral inhibition was assessed using a forced choice go/no-go task that incorporated a variable payoff schedule. Results Administration of ATD resulted in significant reductions in TRP measured in peripheral blood samples, indicating reductions of TRP influx across the blood–brain barrier and related brain 5-HT synthesis. Overall accuracy and response time performance were improved after ATD administration. The ability to adjust behavioral responses to aversive outcome magnitudes and behavioral adjustments following error contingent punishment remained intact after decreased brain 5-HT synthesis. A previously observed dissociation effect of ATD on punishment-induced inhibition was not observed. Conclusions Our results suggest that neurodietary challenges with ATD Moja–De have no detrimental effects on task performance and punishment-related inhibition in healthy adults.
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Affiliation(s)
- Tilman J Gaber
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany
| | - Vita L S Dingerkus
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany
| | - Molly J Crockett
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Sarah Bubenzer-Busch
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany
| | - Katrin Helmbold
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany
| | - Cristina L Sánchez
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany
| | - Brigitte Dahmen
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany
| | - Beate Herpertz-Dahlmann
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany
| | - Florian D Zepf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Aachen & Jülich, Germany.,Institute for Neuroscience and Medicine, Jülich Research Centre, Jülich, Germany.,Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Australia.,Specialised Child and Adolescent Mental Health Services (CAMHS), Department of Health in Western Australia, Perth, WA, Australia;
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32
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Balasubramani PP, Chakravarthy VS, Ravindran B, Moustafa AA. A network model of basal ganglia for understanding the roles of dopamine and serotonin in reward-punishment-risk based decision making. Front Comput Neurosci 2015; 9:76. [PMID: 26136679 PMCID: PMC4469836 DOI: 10.3389/fncom.2015.00076] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 06/02/2015] [Indexed: 01/10/2023] Open
Abstract
There is significant evidence that in addition to reward-punishment based decision making, the Basal Ganglia (BG) contributes to risk-based decision making (Balasubramani et al., 2014). Despite this evidence, little is known about the computational principles and neural correlates of risk computation in this subcortical system. We have previously proposed a reinforcement learning (RL)-based model of the BG that simulates the interactions between dopamine (DA) and serotonin (5HT) in a diverse set of experimental studies including reward, punishment and risk based decision making (Balasubramani et al., 2014). Starting with the classical idea that the activity of mesencephalic DA represents reward prediction error, the model posits that serotoninergic activity in the striatum controls risk-prediction error. Our prior model of the BG was an abstract model that did not incorporate anatomical and cellular-level data. In this work, we expand the earlier model into a detailed network model of the BG and demonstrate the joint contributions of DA-5HT in risk and reward-punishment sensitivity. At the core of the proposed network model is the following insight regarding cellular correlates of value and risk computation. Just as DA D1 receptor (D1R) expressing medium spiny neurons (MSNs) of the striatum were thought to be the neural substrates for value computation, we propose that DA D1R and D2R co-expressing MSNs are capable of computing risk. Though the existence of MSNs that co-express D1R and D2R are reported by various experimental studies, prior existing computational models did not include them. Ours is the first model that accounts for the computational possibilities of these co-expressing D1R-D2R MSNs, and describes how DA and 5HT mediate activity in these classes of neurons (D1R-, D2R-, D1R-D2R- MSNs). Starting from the assumption that 5HT modulates all MSNs, our study predicts significant modulatory effects of 5HT on D2R and co-expressing D1R-D2R MSNs which in turn explains the multifarious functions of 5HT in the BG. The experiments simulated in the present study relates 5HT to risk sensitivity and reward-punishment learning. Furthermore, our model is shown to capture reward-punishment and risk based decision making impairment in Parkinson's Disease (PD). The model predicts that optimizing 5HT levels along with DA medications might be essential for improving the patients' reward-punishment learning deficits.
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Affiliation(s)
| | | | - Balaraman Ravindran
- Department of Computer Science and Engineering, Indian Institute of Technology Madras Chennai, India
| | - Ahmed A Moustafa
- School of Social Sciences and Technology, Marcs Institute for Brain and Behavior, University of Western Sydney Penrith, NSW, Australia ; Department of Veterans Affairs, New Jersey Health Care System East Orange, NJ, USA
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Biskup CS, Gaber T, Helmbold K, Bubenzer-Busch S, Zepf FD. Amino acid challenge and depletion techniques in human functional neuroimaging studies: an overview. Amino Acids 2015; 47:651-83. [DOI: 10.1007/s00726-015-1919-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/09/2015] [Indexed: 01/16/2023]
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34
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Banlaki Z, Elek Z, Nanasi T, Szekely A, Nemoda Z, Sasvari-Szekely M, Ronai Z. Polymorphism in the serotonin receptor 2a (HTR2A) gene as possible predisposal factor for aggressive traits. PLoS One 2015; 10:e0117792. [PMID: 25658328 PMCID: PMC4319849 DOI: 10.1371/journal.pone.0117792] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 12/31/2014] [Indexed: 02/03/2023] Open
Abstract
Aggressive manifestations and their consequences are a major issue of mankind, highlighting the need for understanding the contributory factors. Still, aggression-related genetic analyses have so far mainly been conducted on small population subsets such as individuals suffering from a certain psychiatric disorder or a narrow-range age cohort, but no data on the general population is yet available. In the present study, our aim was to identify polymorphisms in genes affecting neurobiological processes that might explain some of the inter-individual variation between aggression levels in the non-clinical Caucasian adult population. 55 single nucleotide polymorphisms (SNP) were simultaneously determined in 887 subjects who also filled out the self-report Buss-Perry Aggression Questionnaire (BPAQ). Single marker association analyses between genotypes and aggression scores indicated a significant role of rs7322347 located in the HTR2A gene encoding serotonin receptor 2a following Bonferroni correction for multiple testing (p = 0.0007) both for males and females. Taking the four BPAQ subscales individually, scores for Hostility, Anger and Physical Aggression showed significant association with rs7322347 T allele in themselves, while no association was found with Verbal Aggression. Of the subscales, relationship with rs7322347 was strongest in the case of Hostility, where statistical significance virtually equaled that observed with the whole BPAQ. In conclusion, this is the first study to our knowledge analyzing SNPs in a wide variety of genes in terms of aggression in a large sample-size non-clinical adult population, also describing a novel candidate polymorphism as predisposal to aggressive traits.
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Affiliation(s)
- Zsofia Banlaki
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Zsuzsanna Elek
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Tibor Nanasi
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Anna Szekely
- Institute of Psychology, Eotvos Lorand University, Budapest, Hungary
| | - Zsofia Nemoda
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Maria Sasvari-Szekely
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Zsolt Ronai
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
- * E-mail:
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Hägele C, Schlagenhauf F, Rapp M, Sterzer P, Beck A, Bermpohl F, Stoy M, Ströhle A, Wittchen HU, Dolan RJ, Heinz A. Dimensional psychiatry: reward dysfunction and depressive mood across psychiatric disorders. Psychopharmacology (Berl) 2015; 232:331-41. [PMID: 24973896 PMCID: PMC4297301 DOI: 10.1007/s00213-014-3662-7] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 06/16/2014] [Indexed: 10/26/2022]
Abstract
RATIONALE A dimensional approach in psychiatry aims to identify core mechanisms of mental disorders across nosological boundaries. OBJECTIVES We compared anticipation of reward between major psychiatric disorders, and investigated whether reward anticipation is impaired in several mental disorders and whether there is a common psychopathological correlate (negative mood) of such an impairment. METHODS We used functional magnetic resonance imaging (fMRI) and a monetary incentive delay (MID) task to study the functional correlates of reward anticipation across major psychiatric disorders in 184 subjects, with the diagnoses of alcohol dependence (n = 26), schizophrenia (n = 44), major depressive disorder (MDD, n = 24), bipolar disorder (acute manic episode, n = 13), attention deficit/hyperactivity disorder (ADHD, n = 23), and healthy controls (n = 54). Subjects' individual Beck Depression Inventory-and State-Trait Anxiety Inventory-scores were correlated with clusters showing significant activation during reward anticipation. RESULTS During reward anticipation, we observed significant group differences in ventral striatal (VS) activation: patients with schizophrenia, alcohol dependence, and major depression showed significantly less ventral striatal activation compared to healthy controls. Depressive symptoms correlated with dysfunction in reward anticipation regardless of diagnostic entity. There was no significant correlation between anxiety symptoms and VS functional activation. CONCLUSION Our findings demonstrate a neurobiological dysfunction related to reward prediction that transcended disorder categories and was related to measures of depressed mood. The findings underline the potential of a dimensional approach in psychiatry and strengthen the hypothesis that neurobiological research in psychiatric disorders can be targeted at core mechanisms that are likely to be implicated in a range of clinical entities.
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Affiliation(s)
- Claudia Hägele
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany,
| | - Florian Schlagenhauf
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany ,Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Michael Rapp
- Social and Preventive Medicine, University of Potsdam, Potsdam, Germany
| | - Philipp Sterzer
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany ,Berlin School of Mind and Brain, Berlin, Germany
| | - Anne Beck
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Felix Bermpohl
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany ,Berlin School of Mind and Brain, Berlin, Germany
| | - Meline Stoy
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Andreas Ströhle
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany ,Berlin School of Mind and Brain, Berlin, Germany
| | - Hans-Ulrich Wittchen
- Institute of Clinical Psychology and Psychotherapy, Technische Universität Dresden, Dresden, Germany
| | - Raymond J. Dolan
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, WC1N 3BG UK ,Visiting Einstein Fellow, Mind and Brain Centre, Humboldt University, Berlin, Germany
| | - Andreas Heinz
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany ,Berlin School of Mind and Brain, Berlin, Germany
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Sego C, Gonçalves L, Lima L, Furigo IC, Donato J, Metzger M. Lateral habenula and the rostromedial tegmental nucleus innervate neurochemically distinct subdivisions of the dorsal raphe nucleus in the rat. J Comp Neurol 2014; 522:1454-84. [PMID: 24374795 DOI: 10.1002/cne.23533] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 12/23/2013] [Accepted: 12/23/2013] [Indexed: 02/06/2023]
Abstract
The lateral habenula (LHb) is an epithalamic structure differentiated in a medial (LHbM) and a lateral division (LHbL). Together with the rostromedial tegmental nucleus (RMTg), the LHb has been implicated in the processing of aversive stimuli and inhibitory control of monoamine nuclei. The inhibitory LHb influence on midbrain dopamine neurons has been shown to be mainly mediated by the RMTg, a mostly GABAergic nucleus that receives a dominant input from the LHbL. Interestingly, the RMTg also projects to the dorsal raphe nucleus (DR), which also receives direct LHb projections. To compare the organization and transmitter phenotype of LHb projections to the DR, direct and indirect via the RMTg, we first placed injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin into the LHb or the RMTg. We then confirmed our findings by retrograde tracing and investigated a possible GABAergic phenotype of DR-projecting RMTg neurons by combining retrograde tracing with in situ hybridization for GAD67. We found only moderate direct LHb projections to the DR, which mainly emerged from the LHbM and were predominantly directed to the serotonin-rich caudal DR. In contrast, RMTg projections to the DR were more robust, emerged from RMTg neurons enriched in GAD67 mRNA, and were focally directed to a distinctive DR subdivision immunohistochemically characterized as poor in serotonin and enriched in presumptive glutamatergic neurons. Thus, besides its well-acknowledged role as a GABAergic control center for the ventral tegmental area (VTA)-nigra complex, our findings indicate that the RMTg is also a major GABAergic relay between the LHb and the DR.
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Affiliation(s)
- Chemutai Sego
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900, São Paulo, Brazil; Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, 05508-900, São Paulo, Brazil
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The role of serotonin in reward, punishment and behavioural inhibition in humans: insights from studies with acute tryptophan depletion. Neurosci Biobehav Rev 2014; 46 Pt 3:365-78. [PMID: 25195164 DOI: 10.1016/j.neubiorev.2014.07.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 06/19/2014] [Accepted: 07/28/2014] [Indexed: 01/06/2023]
Abstract
Deakin and Graeff proposed that forebrain 5-hydroxytryptamine (5-HT) projections are activated by aversive events and mediate anticipatory coping responses including avoidance learning and suppression of the fight-flight escape/panic response. Other theories proposed 5-HT mediates aspects of behavioural inhibition or reward. Most of the evidence comes from rodent studies. We review 36 experimental studies in humans in which the technique of acute tryptophan depletion (ATD) was used to explicitly address the role of 5-HT in response inhibition, punishment and reward. ATD did not cause disinhibition of responding in the absence of rewards or punishments (9 studies). A major role for 5-HT in reward processing is unlikely but further tests are warranted by some ATD findings. Remarkably, ATD lessened the ability of punishments (losing points or notional money) to restrain behaviour without affecting reward processing in 7 studies. Two of these studies strongly indicate that ATD blocks 5-HT mediated aversively conditioned Pavlovian inhibition and this can explain a number of the behavioural effects of ATD.
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38
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Balasubramani PP, Chakravarthy VS, Ravindran B, Moustafa AA. An extended reinforcement learning model of basal ganglia to understand the contributions of serotonin and dopamine in risk-based decision making, reward prediction, and punishment learning. Front Comput Neurosci 2014; 8:47. [PMID: 24795614 PMCID: PMC3997037 DOI: 10.3389/fncom.2014.00047] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 03/30/2014] [Indexed: 11/29/2022] Open
Abstract
Although empirical and neural studies show that serotonin (5HT) plays many functional roles in the brain, prior computational models mostly focus on its role in behavioral inhibition. In this study, we present a model of risk based decision making in a modified Reinforcement Learning (RL)-framework. The model depicts the roles of dopamine (DA) and serotonin (5HT) in Basal Ganglia (BG). In this model, the DA signal is represented by the temporal difference error (δ), while the 5HT signal is represented by a parameter (α) that controls risk prediction error. This formulation that accommodates both 5HT and DA reconciles some of the diverse roles of 5HT particularly in connection with the BG system. We apply the model to different experimental paradigms used to study the role of 5HT: (1) Risk-sensitive decision making, where 5HT controls risk assessment, (2) Temporal reward prediction, where 5HT controls time-scale of reward prediction, and (3) Reward/Punishment sensitivity, in which the punishment prediction error depends on 5HT levels. Thus the proposed integrated RL model reconciles several existing theories of 5HT and DA in the BG.
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Affiliation(s)
| | | | - Balaraman Ravindran
- Department of Computer Science and Engineering, Indian Institute of Technology - Madras Chennai, India
| | - Ahmed A Moustafa
- Foundational Processes of Behaviour Research Concentration, Marcs Institute for Brain and Behaviour & School of Social Sciences and Psychology, University of Western Sydney Sydney, NSW, Australia
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Macoveanu J, Knorr U, Skimminge A, Søndergaard MG, Jørgensen A, Fauerholdt-Jepsen M, Paulson OB, Knudsen GM, Siebner HR, Kessing LV. Altered reward processing in the orbitofrontal cortex and hippocampus in healthy first-degree relatives of patients with depression. Psychol Med 2014; 44:1183-1195. [PMID: 23866315 DOI: 10.1017/s0033291713001815] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Healthy first-degree relatives of patients with major depression (rMD+) show brain structure and functional response anomalies and have elevated risk for developing depression, a disorder linked to abnormal serotonergic neurotransmission and reward processing. METHOD In a two-step functional magnetic resonance imaging (fMRI) investigation, we first evaluated whether positive and negative monetary outcomes were differentially processed by rMD+ individuals compared to healthy first-degree relatives of control probands (rMD-). Second, in a double-blinded placebo-controlled randomized trial we investigated whether a 4-week intervention with the selective serotonergic reuptake inhibitor (SSRI) escitalopram had a normalizing effect on behavior and brain responses of the rMD+ individuals. RESULTS Negative outcomes increased the probability of risk-averse choices in the subsequent trial in rMD+ but not in rMD- individuals. The orbitofrontal cortex (OFC) displayed a stronger neural response when subjects missed a large reward after a low-risk choice in the rMD+ group compared to the rMD- group. The enhanced orbitofrontal response to negative outcomes was reversed following escitalopram intervention compared to placebo. Conversely, for positive outcomes, the left hippocampus showed attenuated response to high wins in the rMD+ compared to the rMD- group. The SSRI intervention reinforced the hippocampal response to large wins. A subsequent structural analysis revealed that the abnormal neural responses were not accounted for by changes in gray matter density in rMD+ individuals. CONCLUSIONS Our study in first-degree relatives of depressive patients showed abnormal brain responses to aversive and rewarding outcomes in regions known to be dysfunctional in depression. We further confirmed the reversal of these aberrant activations with SSRI intervention.
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Affiliation(s)
- J Macoveanu
- Danish Research Center for Magnetic Resonance, Hvidovre Hospital, Copenhagen University Hospital, Denmark
| | - U Knorr
- Psychiatric Center Copenhagen, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - A Skimminge
- Danish Research Center for Magnetic Resonance, Hvidovre Hospital, Copenhagen University Hospital, Denmark
| | - M G Søndergaard
- Psychiatric Center Copenhagen, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - A Jørgensen
- Psychiatric Center Copenhagen, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - M Fauerholdt-Jepsen
- Psychiatric Center Copenhagen, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - O B Paulson
- Danish Research Center for Magnetic Resonance, Hvidovre Hospital, Copenhagen University Hospital, Denmark
| | - G M Knudsen
- Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - H R Siebner
- Danish Research Center for Magnetic Resonance, Hvidovre Hospital, Copenhagen University Hospital, Denmark
| | - L V Kessing
- Psychiatric Center Copenhagen, Rigshospitalet, Copenhagen University Hospital, Denmark
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40
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Vassena E, Silvetti M, Boehler CN, Achten E, Fias W, Verguts T. Overlapping neural systems represent cognitive effort and reward anticipation. PLoS One 2014; 9:e91008. [PMID: 24608867 PMCID: PMC3946624 DOI: 10.1371/journal.pone.0091008] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/07/2014] [Indexed: 11/18/2022] Open
Abstract
Anticipating a potential benefit and how difficult it will be to obtain it are valuable skills in a constantly changing environment. In the human brain, the anticipation of reward is encoded by the Anterior Cingulate Cortex (ACC) and Striatum. Naturally, potential rewards have an incentive quality, resulting in a motivational effect improving performance. Recently it has been proposed that an upcoming task requiring effort induces a similar anticipation mechanism as reward, relying on the same cortico-limbic network. However, this overlapping anticipatory activity for reward and effort has only been investigated in a perceptual task. Whether this generalizes to high-level cognitive tasks remains to be investigated. To this end, an fMRI experiment was designed to investigate anticipation of reward and effort in cognitive tasks. A mental arithmetic task was implemented, manipulating effort (difficulty), reward, and delay in reward delivery to control for temporal confounds. The goal was to test for the motivational effect induced by the expectation of bigger reward and higher effort. The results showed that the activation elicited by an upcoming difficult task overlapped with higher reward prospect in the ACC and in the striatum, thus highlighting a pivotal role of this circuit in sustaining motivated behavior.
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Affiliation(s)
- Eliana Vassena
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University Hospital, Ghent, Belgium
- * E-mail:
| | - Massimo Silvetti
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University Hospital, Ghent, Belgium
| | - Carsten N. Boehler
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University Hospital, Ghent, Belgium
| | - Eric Achten
- Ghent Institute for Functional and Metabolic Imaging, Ghent University Hospital, Ghent, Belgium
| | - Wim Fias
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University Hospital, Ghent, Belgium
| | - Tom Verguts
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University Hospital, Ghent, Belgium
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Tobia MJ, Guo R, Schwarze U, Boehmer W, Gläscher J, Finckh B, Marschner A, Büchel C, Obermayer K, Sommer T. Neural systems for choice and valuation with counterfactual learning signals. Neuroimage 2013; 89:57-69. [PMID: 24321554 DOI: 10.1016/j.neuroimage.2013.11.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 11/24/2013] [Accepted: 11/28/2013] [Indexed: 10/25/2022] Open
Abstract
The purpose of this experiment was to test a computational model of reinforcement learning with and without fictive prediction error (FPE) signals to investigate how counterfactual consequences contribute to acquired representations of action-specific expected value, and to determine the functional neuroanatomy and neuromodulator systems that are involved. 80 male participants underwent dietary depletion of either tryptophan or tyrosine/phenylalanine to manipulate serotonin (5HT) and dopamine (DA), respectively. They completed 80 rounds (240 trials) of a strategic sequential investment task that required accepting interim losses in order to access a lucrative state and maximize long-term gains, while being scanned. We extended the standard Q-learning model by incorporating both counterfactual gains and losses into separate error signals. The FPE model explained the participants' data significantly better than a model that did not include counterfactual learning signals. Expected value from the FPE model was significantly correlated with BOLD signal change in the ventromedial prefrontal cortex (vmPFC) and posterior orbitofrontal cortex (OFC), whereas expected value from the standard model did not predict changes in neural activity. The depletion procedure revealed significantly different neural responses to expected value in the vmPFC, caudate, and dopaminergic midbrain in the vicinity of the substantia nigra (SN). Differences in neural activity were not evident in the standard Q-learning computational model. These findings demonstrate that FPE signals are an important component of valuation for decision making, and that the neural representation of expected value incorporates cortical and subcortical structures via interactions among serotonergic and dopaminergic modulator systems.
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Affiliation(s)
- M J Tobia
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany.
| | - R Guo
- Department of Software Engineering and Theoretical Computer Science, School IV Electrical Engineering and Computer Science, Technische Universität Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, Germany
| | - U Schwarze
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - W Boehmer
- Department of Software Engineering and Theoretical Computer Science, School IV Electrical Engineering and Computer Science, Technische Universität Berlin, Germany
| | - J Gläscher
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - B Finckh
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - A Marschner
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - C Büchel
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - K Obermayer
- Department of Software Engineering and Theoretical Computer Science, School IV Electrical Engineering and Computer Science, Technische Universität Berlin, Germany; Bernstein Center for Computational Neuroscience Berlin, Germany
| | - T Sommer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
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Geurts DEM, Huys QJM, den Ouden HEM, Cools R. Serotonin and aversive Pavlovian control of instrumental behavior in humans. J Neurosci 2013; 33:18932-9. [PMID: 24285898 PMCID: PMC6618702 DOI: 10.1523/jneurosci.2749-13.2013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 10/17/2013] [Accepted: 10/17/2013] [Indexed: 11/21/2022] Open
Abstract
Adaptive decision-making involves interaction between systems regulating Pavlovian and instrumental control of behavior. Here we investigate in humans the role of serotonin in such Pavlovian-instrumental transfer in both the aversive and the appetitive domain using acute tryptophan depletion, known to lower central serotonin levels. Acute tryptophan depletion attenuated the inhibiting effect of aversive Pavlovian cues on instrumental behavior, while leaving unaltered the activating effect of appetitive Pavlovian cues. These data suggest that serotonin is selectively involved in Pavlovian inhibition due to aversive expectations and have implications for our understanding of the mechanisms underlying a range of affective, impulsive, and aggressive neuropsychiatric disorders.
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Affiliation(s)
- Dirk E M Geurts
- Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behavior, Centre for Cognitive Neuroimaging and Department of Psychiatry, 6500 HB, Nijmegen, The Netherlands, Gatsby Computational Neuroscience Unit and Wellcome Trust Centre for Neuroimaging, UCL, WC1N 3AR, London, United Kingdom, Translational Neuromodeling Unit, ETH, University of Zurich, CH-8032 Zurich, Switzerland, and Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, CH-8032 Zurich, Switzerland
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43
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Feedback-related negativity codes outcome valence, but not outcome expectancy, during reversal learning. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2013; 13:737-46. [DOI: 10.3758/s13415-013-0150-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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44
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Herzallah MM, Moustafa AA, Natsheh JY, Abdellatif SM, Taha MB, Tayem YI, Sehwail MA, Amleh I, Petrides G, Myers CE, Gluck MA. Learning from negative feedback in patients with major depressive disorder is attenuated by SSRI antidepressants. Front Integr Neurosci 2013; 7:67. [PMID: 24065894 PMCID: PMC3779792 DOI: 10.3389/fnint.2013.00067] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 08/26/2013] [Indexed: 11/13/2022] Open
Abstract
One barrier to interpreting past studies of cognition and major depressive disorder (MDD) has been the failure in many studies to adequately dissociate the effects of MDD from the potential cognitive side effects of selective serotonin reuptake inhibitors (SSRIs) use. To better understand how remediation of depressive symptoms affects cognitive function in MDD, we evaluated three groups of subjects: medication-naïve patients with MDD, medicated patients with MDD receiving the SSRI paroxetine, and healthy control (HC) subjects. All were administered a category-learning task that allows for dissociation between learning from positive feedback (reward) vs. learning from negative feedback (punishment). Healthy subjects learned significantly better from positive feedback than medication-naïve and medicated MDD groups, whose learning accuracy did not differ significantly. In contrast, medicated patients with MDD learned significantly less from negative feedback than medication-naïve patients with MDD and healthy subjects, whose learning accuracy was comparable. A comparison of subject’s relative sensitivity to positive vs. negative feedback showed that both the medicated MDD and HC groups conform to Kahneman and Tversky’s (1979) Prospect Theory, which expects losses (negative feedback) to loom psychologically slightly larger than gains (positive feedback). However, medicated MDD and HC profiles are not similar, which indicates that the state of medicated MDD is not “normal” when compared to HC, but rather balanced with less learning from both positive and negative feedback. On the other hand, medication-naïve patients with MDD violate Prospect Theory by having significantly exaggerated learning from negative feedback. This suggests that SSRI antidepressants impair learning from negative feedback, while having negligible effect on learning from positive feedback. Overall, these findings shed light on the importance of dissociating the cognitive consequences of MDD from those of SSRI treatment, and from cognitive evaluation of MDD subjects in a medication-naïve state before the administration of antidepressants. Future research is needed to correlate the mood-elevating effects and the cognitive balance between reward- and punishment-based learning related to SSRIs.
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Affiliation(s)
- Mohammad M Herzallah
- Al-Quds Cognitive Neuroscience Lab, Faculty of Medicine, Al-Quds University Abu Dis, Palestinian Territories ; Center for Molecular and Behavioral Neuroscience, Rutgers University Newark, NJ, USA
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45
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Robinson OJ, Overstreet C, Allen PS, Letkiewicz A, Vytal K, Pine DS, Grillon C. The role of serotonin in the neurocircuitry of negative affective bias: serotonergic modulation of the dorsal medial prefrontal-amygdala 'aversive amplification' circuit. Neuroimage 2013; 78:217-23. [PMID: 23583742 DOI: 10.1016/j.neuroimage.2013.03.075] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 03/27/2013] [Accepted: 03/31/2013] [Indexed: 10/26/2022] Open
Abstract
Serotonergic medications can mitigate the negative affective biases in disorders such as depression or anxiety, but the neural mechanism by which this occurs is largely unknown. In line with recent advances demonstrating that negative affective biases may be driven by specific medial prefrontal-amygdala circuitry, we asked whether serotonin manipulation can alter affective processing within a key dorsal medial prefrontal-amygdala circuit: the putative human homologue of the rodent prelimbic-amygdala circuit or 'aversive amplification' circuit. In a double-blind, placebo-controlled crossover pharmaco-fMRI design, subjects (N=19) performed a forced-choice face identification task with word distractors in an fMRI scanner over two separate sessions. On one session subjects received dietary depletion of the serotonin precursor tryptophan while on the other session they received a balanced placebo control diet. Results showed that dorsal medial prefrontal responding was elevated in response to fearful relative to happy faces under depletion but not placebo. This negative bias under depletion was accompanied by a corresponding increase in positive dorsal medial prefrontal-amygdala functional connectivity. We therefore conclude that serotonin depletion engages a prefrontal-amygdala circuit during the processing of fearful relative to happy face stimuli. This same 'aversive amplification' circuit is also engaged during anxiety induced by shock anticipation. As such, serotonergic projections may inhibit engagement of the 'aversive amplification' circuit and dysfunction in this projection may contribute to the negative affective bias in mood and anxiety disorders. These findings thus provide a promising explanation for the role of serotonin and serotonergic medications in the neurocircuitry of negative affective bias.
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Affiliation(s)
- Oliver J Robinson
- Section on Neurobiology of Fear and Anxiety, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA.
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46
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Variants at serotonin transporter and 2A receptor genes predict cooperative behavior differentially according to presence of punishment. Proc Natl Acad Sci U S A 2013; 110:3955-60. [PMID: 23431136 DOI: 10.1073/pnas.1216841110] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Punishment of free-riding has been implicated in the evolution of cooperation in humans, and yet mechanisms for punishment avoidance remain largely uninvestigated. Individual variation in these mechanisms may stem from variation in the serotonergic system, which modulates processing of aversive stimuli. Functional serotonin gene variants have been associated with variation in the processing of aversive stimuli and widely studied as risk factors for psychiatric disorders. We show that variants at the serotonin transporter gene (SLC6A4) and serotonin 2A receptor gene (HTR2A) predict contributions to the public good in economic games, dependent upon whether contribution behavior can be punished. Participants with a variant at the serotonin transporter gene contribute more, leading to group-level differences in cooperation, but this effect dissipates in the presence of punishment. When contribution behavior can be punished, those with a variant at the serotonin 2A receptor gene contribute more than those without it. This variant also predicts a more stressful experience of the games. The diversity of institutions (including norms) that govern cooperation and punishment may create selective pressures for punishment avoidance that change rapidly across time and space. Variant-specific epigenetic regulation of these genes, as well as population-level variation in the frequencies of these variants, may facilitate adaptation to local norms of cooperation and punishment.
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47
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Stress increases aversive prediction error signal in the ventral striatum. Proc Natl Acad Sci U S A 2013; 110:4129-33. [PMID: 23401511 DOI: 10.1073/pnas.1213923110] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
From job interviews to the heat of battle, it is evident that people think and learn differently when stressed. In fact, learning under stress may have long-term consequences; stress facilitates aversive conditioning and associations learned during extreme stress may result in debilitating emotional responses in posttraumatic stress disorder. The mechanisms underpinning such stress-related associations, however, are unknown. Computational neuroscience has successfully characterized several mechanisms critical for associative learning under normative conditions. One such mechanism, the detection of a mismatch between expected and observed outcomes within the ventral striatum (i.e., "prediction errors"), is thought to be a critical precursor to the formation of new stimulus-outcome associations. An untested possibility, therefore, is that stress may affect learning via modulation of this mechanism. Here we combine a translational model of stress with a cognitive neuroimaging paradigm to demonstrate that stress significantly increases ventral striatum aversive (but not appetitive) prediction error signal. This provides a unique account of the propensity to form threat-related associations under stress with direct implications for our understanding of both normal stress and stress-related disorders.
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48
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Zeeb FD, Wong AC, Winstanley CA. Differential effects of environmental enrichment, social-housing, and isolation-rearing on a rat gambling task: dissociations between impulsive action and risky decision-making. Psychopharmacology (Berl) 2013; 225:381-95. [PMID: 22864967 DOI: 10.1007/s00213-012-2822-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 07/19/2012] [Indexed: 01/22/2023]
Abstract
RATIONALE Decision-making deficits, measured using the Iowa Gambling Task (IGT), are observed in many psychiatric populations. Additionally, evidence suggests that the environment also influences the development of these same disorders. OBJECTIVE To determine the direct influence of the environment on decision-making by utilizing the rat gambling task (rGT), a risky decision-making test modeled after the IGT. METHODS Male rats reared in isolation, in pairs, or in an enriched environment were trained on the rGT as adults. During the rGT, animals chose from four different options. The optimal strategy on the rGT and IGT is the same: to favor options associated with smaller immediate rewards and less punishment/loss. Impulsive action is also measured during rGT performance by recording the number of premature responses made, similar to the five-choice serial reaction time task. RESULTS Compared to pair-housed rats, isolated and environmentally enriched rats were slower at learning the optimal strategy. However, following training, only isolation-reared rats chose the disadvantageous options more often. Amphetamine altered decision-making on the rGT in socially housed animals, yet isolates were unaffected. Conversely, amphetamine increased premature responding similarly in all groups. This increase was attenuated by prior administration of a dopamine D(1) or D(2) antagonist; however, the ability of amphetamine to alter decision-making was not blocked by either drug. CONCLUSIONS Housing environment affects animals' ability to learn and perform a decision-making task. Additionally, amphetamine's effect on impulsive action appears to be mediated by the dopaminergic system, whereas its effect on risky decision-making may be mediated by other neurotransmitters.
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Affiliation(s)
- Fiona D Zeeb
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, V6T 1Z4, Canada.
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49
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Hindi Attar C, Finckh B, Büchel C. The influence of serotonin on fear learning. PLoS One 2012; 7:e42397. [PMID: 22879964 PMCID: PMC3411733 DOI: 10.1371/journal.pone.0042397] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/04/2012] [Indexed: 11/18/2022] Open
Abstract
Learning of associations between aversive stimuli and predictive cues is the basis of Pavlovian fear conditioning and is driven by a mismatch between expectation and outcome. To investigate whether serotonin modulates the formation of such aversive cue-outcome associations, we used functional magnetic resonance imaging (fMRI) and dietary tryptophan depletion to reduce brain serotonin (5-HT) levels in healthy human subjects. In a Pavlovian fear conditioning paradigm, 5-HT depleted subjects compared to a non-depleted control group exhibited attenuated autonomic responses to cues indicating the upcoming of an aversive event. These results were closely paralleled by reduced aversive learning signals in the amygdala and the orbitofrontal cortex, two prominent structures of the neural fear circuit. In agreement with current theories of serotonin as a motivational opponent system to dopamine in fear learning, our data provide first empirical evidence for a role of serotonin in representing formally derived learning signals for aversive events.
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Affiliation(s)
- Catherine Hindi Attar
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Acute tryptophan depletion increases translational indices of anxiety but not fear: serotonergic modulation of the bed nucleus of the stria terminalis? Neuropsychopharmacology 2012; 37:1963-71. [PMID: 22491355 PMCID: PMC3376328 DOI: 10.1038/npp.2012.43] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Serotonin is strongly implicated in the mammalian stress response, but surprisingly little is known about its mode of action. Recent data suggest that serotonin can inhibit aversive responding in humans, but this remains underspecified. In particular, data in rodents suggest that global serotonin depletion may specifically increase long-duration bed nucleus of the stria terminalis (BNST)-mediated aversive responses (ie, anxiety), but not short-duration BNST-independent responses (ie, fear). Here, we extend these findings to humans. In a balanced, placebo-controlled crossover design, healthy volunteers (n=20) received a controlled diet with and without the serotonin precursor tryptophan (acute tryptophan depletion; ATD). Aversive states were indexed by translational acoustic startle measures. Fear and anxiety were operationally defined as the increase in startle reactivity during short- and long-duration threat periods evoked by predictable shock (fear-potentiated startle) and by the context in which the shocks were administered (anxiety-potentiated startle), respectively. ATD significantly increased long-duration anxiety-potentiated startle but had no effect on short-duration fear-potentiated startle. These results suggest that serotonin depletion in humans selectively increases anxiety but not fear. Current translational frameworks support the proposition that ATD thus disinhibits dorsal raphé-originating serotonergic control of corticotropin-releasing hormone-mediated excitation of the BNST. This generates a candidate neuropharmacological mechanism by which depleted serotonin may increase response to sustained threats, alongside clear implications for our understanding of the manifestation and treatment of mood and anxiety disorders.
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